DESCRIPTION The objective of this proposed project is the elucidation of the mechanism of double-stranded (ds) RNA condensation dsRNA, the biological mechanism in genome packaging, has received a significant amount of attention because of its importance in the field of non-viral gene delivery. Yet, dsRNA condensation has received a complete lack of attention has a complete lack of attention despite the packaging of genomic dsRNA in certain viruses or associations of dsRNA regions in commonly found single-stranded RNA with proteins. A primary goal of this electron microscopy will be used to follow the condensation kinetics and aggregate morphologies. The effects of ligand structure and mobility on dsRNA condensation will also be studied using cartionic ligands commonly used to condense dsDNA. The effect of dielectric constant on dsRNA condensation will be addressed using water-alcohol mixtures to determine the roles of helical charge density and stiffness. The final goal of this project is a definitive comparison of dsDNA and dsRNA fragment of equal contour.